The present invention relates to an arrangement which includes sticking knife for withdrawing blood from slaughtered animals. The sticking knife has a hollow handle whose one end is connectible to a hose and whose other end has a blade. The arrangement includes a knife retainer for engaging the body of the animal, when the sticking knife has been stuck into the animal, and an operator which is connected to said knife retainer to move it between a sticking position and an engaging position. The invention also relates to a sticking knife fitted with such an arrangement.
Sticking knives are used in slaughtering lines in slaughtered houses for withdrawing blood from slaughter animals. The hanging or lying slaughtered animals are transported past a sticking station where a sticker stands ready with a sticking knife. The sticking knife is connected to a vessel via a hose. The sticker sticks the knife into the neck of the animal, and blood flows via the hose down into the vessel. The withdrawal of blood takes 12-60 seconds. The pressure from the escaping blood and the weight of the sticking knife force the sticker to keep the knife inserted in the sticking wound during the entire blood-withdrawing operation. This applies particularly to slaughtered animals which hang. The sticker's working posture may eventually cause strain or joint injuries.
After each animal, the sticking knife must be cleaned and sterilised.
Further on in the slaughtering line, a veterinarian inspects the slaughtered animals. Should he or she find a disease in the animal, this animal must be rejected. Also, the withdrawn blood must be rejected. As a result, high demands are placed on the hygienic conditions in the blood-withdrawing equipment. It must be possible to clean the sticking knife so that there is no remainder of blood on the sticking knife after cleaning. Further, the cleaning operation must be effected during a limited time, owing to the slaughtering speed required in modern slaughter-houses.
SE 412,835 discloses a slaughtering knife having a piston-and-cylinder assembly which is mounted on the knife. When the knife has been stuck into the animal, the assembly is activated so that the piston rod is ejected from the cylinder to engage the sticking wound. As a result, the knife is retained in the wound.
However, this design suffers from a number of drawbacks. There is an obvious risk that blood and fragments of meat accompany the piston rod into the cylinder, when the assembly is deactivated. The piston-and-cylinder assembly thus must be dismantled in the cleaning operation, which makes it unrealistic to believe that cleaning and sterilising is effected after each sticking operation. Moreover, there is a risk that the piston-and-cylinder assembly jams, since the cylinder and the piston rod are curved. A design according to the above-mentioned publication would not comply with today's hygienic and veterinary standards in a modern slaughter-house.